The invention concerns a process for the insertion of wire in the form of a field coil between the pole horns and the stator wall of a double-pole stator of an electrical machine. The invention also covers a device suitable for performance of the process and a plant for simultaneous winding of several stator halves.
Double-pole stators of electric motors with a collector rotor have a closed stator wall with two opposing pairs of pole horns which partly cover the external diameter of the collector rotor arranged in the central axis of the stator. The wire consisting of copper or the field coils made from this are arranged between the pole horns and the stator wall.
To wind the field coils of a single-piece double-pole stator, needle winding machines are known with which the two opposing field coils can be wound simultaneously directly in the grooves between the stator wall and the pole horns. Here the wire is threaded into the base of the groove over winding accessories. In a variant, winding takes place without winding accessories but with a controlled spreadable wire guide.
Another possibility for winding stators, in particular for small electric motors, is a two-piece double-pole stator known from DE-A-40 37 953. Here, the individual field coils are preproduced by winding on a multiple layer winding machine, the coil legs isolated and the connecting strands applied at the winding start and end. The field coils are inserted and fixed in the groove in the stator halves bordered by the stator wall and pole horns. The two halves are then joined together to form the stator.
Measurements on collector motors have shown that when the pole horns largely cover the rotor external diameter, on corresponding winding a high motor power results. Such a change in sheet cutting of stator stampings made for example by punch bundling of individual laminations would, in a single-piece and consequently closed stator, lead to the space between the pole horns no longer being sufficient for winding with the said needle winding machines.
The invention is based on the task of creating an efficient process of the type described initially and a device suitable for its performance.
To solve the task of the invention with regard to the process, the stator consists of two stator halves and the wire to form the field coil is inserted by way of a winding arm rotating about a rotation axis lying perpendicular to the stator axis, where during the winding process, for temporary formation of an enlarged insert groove for the wire, a winding accessory is laid against the outer edge of the armature stampings or stator and the free end of the pole horns are covered with a wire guide sleeve.
The core of the invention is to separate the sheet cut in the area of the neutral zone and insert the coils of the individual stator halves directly with a winding arm (flyer). In this way it is possible to wind several stator halves simultaneously. Furthermore, the geometric structure of the sheet cut for direct winding by means of a flyer results in a higher filling level of the groove with wire and a lower width, for example of the stator or armature stampings produced by punch bundling of individual laminations, which is advantageous, in particular, for the development of small electrical devices.
Further advantages of the process according to the invention lie in that the coil ends can be laid to terminals on the winding machine. Also, the punch-bundled stator halves can be oversprayed with plastic, which substantially simplifies the groove isolation.
Suitably, the winding arm and the wire guide sleeve can be moved along the rotation axis.
A suitable possibility for connecting the stator halves after winding is for each pair of stator halves to be assembled into a stator by way of a tongue and groove connection. To form the tongue and groove connection, for example each stator half can have a linear tongue of dovetail cross-section and a correspondingly under-cut linear groove.
Advantageously, at the side of each stator half is arranged a plastic body of electrically isolating material with connection elements for contact elements inset therein.
A device suitable for performing the process for winding wire field coils between the pole horns and stator wall of a double-pole stator of an electrical machine, the stator of which is formed in two parts for winding the field coils, is characterised by a winding arm rotatable about a rotation axis, a winding accessory to be laid during the winding process against the stator wall of the stator half to be wound, and a wire guide sleeve laid against the pole horns during the winding process, whereby the winding accessory and the wire guide sleeve form parts of an insert groove.
The winding arm and guide sleeve are preferably movable along the rotation axis.
For systematic production of stators, in particular a plant is suitable for simultaneous winding of several stator halves of two-piece double-pole stators of electrical machines. The plant has a multiplicity of winding stations corresponding to the devices described above and arranged along a transport device. The individual winding stations can preferably be driven by way of a common drive motor.